Fig. 5

Comparative analysis of human and mouse circRNAs. a High conservation of circRNA hosting genes between human and mouse pre-implantation embryos. The Venn diagram shows that the majority of genes that express circRNAs in mouse also produce circular transcripts in human embryos. b GO analysis of the top enriched terms of the circRNA hosting genes in human pre-implantation embryos. c The box plots show the numbers of expressed circRNA hosting genes in human embryos (in red) and mouse embryos (in blue), during pre-implantation development, and the number was normalized to the total mapped reads (in millions) after subsampling the sequencing data. d Expression level of circRNA hosting genes in human embryo and mouse embryo. All circRNA hosting genes are plotted according to the value of log₁₀ of (max RPKM during pre-implantation) in human and mouse embryo, respectively. e Heat map of circularized level of highly expressed circRNA hosting genes (RPKM >10) during human and mouse pre-implantation development. The numbers of circular isoforms from each hosting gene were presented and the columns on the top of the heat map show the average number of circular isoforms from each hosting gene who were producing circular transcripts at this stage. The number of circRNA isoforms is frequently higher than that in mouse. The shared, human-specific, and mouse-specific hosting genes are presented, respectively. f Box plots show the distribution of the length of introns flanking the back-spliced sites from the highly expressed hosting genes after subsampling the sequencing data. The median value of intron length is shown in the box. The back-spliced sites of human-specific and mouse-specific circRNAs are converted using liftover tool, respectively. The numbers of introns are indicated in the bracket